There have been designed many engines with a rotating block of a rotational shape with radially situated cylinders with pistons and an outer stationary case with an intake and/or exhaust port. The rotating cylinder block together with the stationary case work like a rotary valve. There are well known designs of two-stroke as well as four-stroke engines, two, three and multi-cylinder arrangements. Some engines have been equipped with the crankshaft mechanism and some have been equipped with other known mechanisms for transferring the motion of the piston to the shaft. None of those designs has achieved wider enlargement and utilization despite the undoubted potential. There are many reasons why these engines were not successful. The main reason is that the seal between the rotating block and the stationary case was not optimally designed. Mostly, the seal between cylinder space and the stationary case was done by means of sealing elements that were placed in the rotating cylinder block. Those sealing elements were then exposed to centrifugal forces that result from rotation of the rotating block. Together with increasing revolutions that leads to significant stress of these sealing elements, to high friction losses and lubrication problems.
Such designs are described e.g. in documents DE 2732779, FR 2767156A1.
There have been also designs with a seal that is placed in the stationary case of the engine. The most simple is a seal in the form of rings that are placed on both sides of the perimeter of the rotating block. Another seal is done by transverse sealing strips that are placed in the stationary case in the transverse direction with respect to the motion of the perimeter of the rotating block. Such designs are described e.g. in documents FR 2639676A1, U.S. Pat. No. 1,705,130A, W0 9823850A1, W0 8302642A1, etc. This solution is advantageous due to absence of centrifugal forces that act on the sealing parts. Due to minimizing volume of interstices in the combustion space it is necessary to place the side sealing rings as close to cylinder bores as possible. If the side sealing parts are too close to the cylinder bore, then the transverse sealing strips extend too little beyond the cylinder bore, when these cylinder bores are passing these sealing strips. That would increase wear and decrease tightness and durability of the sealing strips. Due to the total length of the seal of the space with high pressure it is necessary to achieve as perfect sealing as possible. Untightness in the place, where the sealing strips and rings meet, is a problem. Gas can blow by through both clearance between sealing parts and particularly at the bottom of their connected grooves. If there is more than one side sealing ring, gas that overcomes the first ring can further blow through the circumferential interstice between side rings.